The fine structure of the "germinal cytoplasm" in the egg ofXenopus laevis.

1. The fine structure of the "germinal cytoplasm" of the dividing egg ofXenopus laevis has been studied. Mitochondria which occur in great numbers and electron-dense bodies associated with them are the two characteristic components of the so-called "germinal cytoplasm". 2. The electron-dense bodies are composed of granular and fibrillar elements and often contain an internal light area. Long fibrillar elements have been found within the light area. The organization of the electron-dense bodies is strongly reminiscent of that of the polar granules inDrosophila.